Asenapine is a compound for use in the treatment of central nervous system disorders, in particular schizophrenia. The chemical name of asenapine is trans-5-chloro-2-methyl-2,3,3a,12b-tetrahydro-1H-dibenz[2,3:6,7]oxepino[4,5-c]pyrrole and the preparation thereof is disclosed in U.S. Pat. No. 4,145,434.